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Outlook randomly resolves to x500 address instead of SMTP RRS feed

  • Question

  • Hello,

    Outlook for a few users randomly resolves to their x500 address in the to or from field.

    Re-resolving their names results in names resolving to SMTP address.

    Why would Outlook sometimes resolve to x500? is there documentation somewhere that explains the resolution and how Outlook is inserting x500? I'm using MAPI.

    Thanks,

    Shashank

    Monday, June 17, 2019 8:39 PM

Answers

  • Hi Shashank,

    Are there any changes made to these users' address before this issue occur?

    I searched via both Outlook side and Exchange side and in case this issue lies on cached addresses. Please follow the steps to empty the Auto complete list and update OAB.

    1. Go to File > Options > Mail.

    2. Under Send messages section, click Empty Auto-Complete List.


    3. Click OK.

    4. Go to Send/Receive tab > Send/Receive Groups > Download Address Book.

    5. Untick Download changes since last Send/Receive” and then click OK.

    Besides, I also found this link. From KelvinD’s reply, we can change the properties of problematic user account in EAC to test the results.

    1. Run the cmdlet below to check current X500 value:

    Get-Mailbox -Identity user005 | ft legacyExchangeDN

    2. Open ECP, select the problematic user account, properties, email address, click 'add', add a legacy email address of type X500 to the user account. The format like:

    /O=FIRST ORGANIZATION/OU=EXCHANGE ADMINISTRATIVE GROUP (FYDIBOHF23SPDLT)/CN=RECIPIENTS/CN=username@domain.com

    Hope the information is helpful to you.

    Regards,

    Perry


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    • Edited by Perry-Pan Wednesday, June 19, 2019 5:00 AM
    • Marked as answer by Shaak1 Tuesday, June 25, 2019 2:15 PM
    Wednesday, June 19, 2019 4:59 AM

All replies

  • hi Shashank,

    You most likely could be referring to LegacyExchangeDN entry. By design once emails hit exchange servers Outlook will display users display name backed by LegacyExchangeDN. If user leaves organisation you will not see display name since user will not be in address book and you will only see LegacyExchangeDN that looks like an CN entry. 

    Can you please share what entry you see.. you may remove your organisation details and sway with something like mycompany. 

    Thanks

    Rajan Katwal

    • Proposed as answer by Perry-Pan Tuesday, June 18, 2019 5:44 AM
    • Unproposed as answer by Perry-Pan Wednesday, June 19, 2019 4:53 AM
    Tuesday, June 18, 2019 12:08 AM
  • hi Shashank,

    Just check if the reply is helpful to you. If you have further concern, please feel free to tell us.

    Regards,

    Perry


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.


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    • Edited by Perry-Pan Wednesday, June 19, 2019 5:44 AM
    Tuesday, June 18, 2019 6:17 AM
  • Hello,

    These are active users and only about 20 of them dispersed globally are seeing this issue. 1 out of 20 times outlook client resolves an active user recipient internal to our organization as their x500. In this case the mail is still in "drafts", that is not sent, resolving the name before sending resolves to x500. A retry results display name showing up (expected result). There are 2 or 3 x500 in proxy addresses from various migrations, don't think that matters but thought you should know.

    </o=MMS/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=username>.  

    Thanks for your help.

    Tuesday, June 18, 2019 2:52 PM
  • Hi Shashank,

    Are there any changes made to these users' address before this issue occur?

    I searched via both Outlook side and Exchange side and in case this issue lies on cached addresses. Please follow the steps to empty the Auto complete list and update OAB.

    1. Go to File > Options > Mail.

    2. Under Send messages section, click Empty Auto-Complete List.


    3. Click OK.

    4. Go to Send/Receive tab > Send/Receive Groups > Download Address Book.

    5. Untick Download changes since last Send/Receive” and then click OK.

    Besides, I also found this link. From KelvinD’s reply, we can change the properties of problematic user account in EAC to test the results.

    1. Run the cmdlet below to check current X500 value:

    Get-Mailbox -Identity user005 | ft legacyExchangeDN

    2. Open ECP, select the problematic user account, properties, email address, click 'add', add a legacy email address of type X500 to the user account. The format like:

    /O=FIRST ORGANIZATION/OU=EXCHANGE ADMINISTRATIVE GROUP (FYDIBOHF23SPDLT)/CN=RECIPIENTS/CN=username@domain.com

    Hope the information is helpful to you.

    Regards,

    Perry


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.


    Click here to learn more. Visit the dedicated forum to share, explore and talk to experts about Microsoft Teams.

    • Edited by Perry-Pan Wednesday, June 19, 2019 5:00 AM
    • Marked as answer by Shaak1 Tuesday, June 25, 2019 2:15 PM
    Wednesday, June 19, 2019 4:59 AM
  • Hello,

    I'm looking to understand under what conditions would Outlook client resolve to an x500 approx. 1 out of 20 times. It can't be the OAB because without downloading a fresh copy, just doing a refresh on the name resolution changes it to what one would expect.

    The x500 entry is already in proxy addresses and is valid, but why would Outlook client before sending it resolve to x500 only a few times randomly. Does anyone have a flow somewhere to understand Outlook client's name resolution logic? and it isn't always addresses in "to", it does that to "from" too but mostly "to"

    This screenshot of Outlook hopefully explains further what i'm talking about. This mail has the "from" resolving to x500 address on user's outlook client for their own account. Why would Outlook show x500 on someone's own account and then on a second attempt resolve to what it should be.

    Thanks


    • Edited by Shaak1 Wednesday, June 19, 2019 3:04 PM
    Wednesday, June 19, 2019 3:00 PM
  • I’ve done lots of research and find following information:

    • user account is re-enabled
    • x500 address has been changed before
    • cached address information not update
    • you’ve made migration before

    This issue could occur under these situation. As this issue occurs randomly, it's hard to directly tell why this occurs. The most recommended way is to add the X500 Proxy Address in the Proxy Address Section of Microsoft Exchange.

     I also find one reply in this thread: Exchange NDR X500 Issue  We may test this too.

    >>After adding those X500 entries in proxyAddresses in AD, updating GAL and OAB, removing all caches from Outlook and downloading the OAB again,

    Regards,

    Perry


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    • Edited by Perry-Pan Friday, June 21, 2019 6:58 AM
    Friday, June 21, 2019 6:57 AM
  • Thanks Perry, all my research also pointed to those but didn't connect the dots because:

    1. x500 is already added in proxy. Infact, 3 of them from 3 migrations
    2. Re-Resolving (Ctrl+K) the address without updating or downloading OAB resolves to the expected form (Display name.

    Caching is my leading suspect where I'm starting to conclude to presume in the lack of direct evidence. My theory on that is: At some point x500 got cached during one of the migrations and now Outlook randomly picks it up every now and then. I will try cleaning out the cache for a few users to confirm and check if the errors still occur 1 in 20.

    Thanks for your time investment in helping out. Thanks to all who replied.

    Friday, June 21, 2019 1:10 PM
  • Thanks Perry, all my research also pointed to those but didn't connect the dots because:

    1. x500 is already added in proxy. Infact, 3 of them from 3 migrations
    2. Re-Resolving (Ctrl+K) the address without updating or downloading OAB resolves to the expected form (Display name.

    Caching is my leading suspect where I'm starting to conclude to presume in the lack of direct evidence. My theory on that is: At some point x500 got cached during one of the migrations and now Outlook randomly picks it up every now and then. I will try cleaning out the cache for a few users to confirm and check if the errors still occur 1 in 20.

    Thanks for your time investment in helping out. Thanks to all who replied.

    You are welcome~

    If there are any updates, you can feel free to post back.

    If you've found a fix, you can also share it here which will greatly benefit other users a lot :)

    Regards,

    Perry


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.


    Click here to learn more. Visit the dedicated forum to share, explore and talk to experts about Microsoft Teams.

    Monday, June 24, 2019 5:04 AM